# corner-diagonals

A skill for diagonal-cut corners and chamfered edges on buttons, cards and panels. Useful when a UI needs sharp geometry instead of rounded pills.

- skill · `type=skill` · Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, OpenCode · 1400 installs · ★ 7001
- Author: MengTo
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/MengTo/Skills/tree/HEAD/agent-skills/web-design/corner-diagonals/SKILL.md
- Updated: 2026-10-25
- HTML: https://affpapa.org/en/nevibecode/skills/corner-diagonals

## What it does

The skill ships CSS tokens and ready `clip-path: polygon(...)` shapes that cut corners on buttons, cards, panels and container shells. Inside are `--corner-cut-sm/md/lg` variables (8px, 14px, 24px), line and fill colors, and three base silhouettes: all corners cut, top-left plus bottom-right, top-right plus bottom-left. For bordered surfaces it uses a `.cut-shell` wrapper with an inner layer that inherits the same polygon through `clip-path: inherit`.

Separate patterns cover primary and secondary buttons, including a gradient outline and a visible focus state. Cut size is meant to scale with the component: 6–10px for small controls, 12–18px for cards, 20–32px for large panels. Buttons keep a 44px minimum height, which is about touch targets rather than looks.

The catch is that `clip-path` trims the border and the hit area along with the background. Leave a rectangular `border` or an invisible click zone and the silhouette still reads, but the button gets harder to hit. The skill lists this under what to avoid: clipping only the background while borders and hit areas stay rectangular. It also warns against mixing rounded pills and chamfered geometry in one layer without a clear hierarchy.

## Install

### Claude Code (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add MengTo/Skills --skill corner-diagonals -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/corner-diagonals/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/corner-diagonals/

### Codex

1. **Skills CLI (Vercel)**
```bash
npx skills add MengTo/Skills --skill corner-diagonals -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/corner-diagonals/SKILL.md` — For all projects use ~/.agents/skills/

### Cursor

1. **Skills CLI (Vercel)**
```bash
npx skills add MengTo/Skills --skill corner-diagonals -a cursor
```

2. **Manually: put the files in place**
- File: `.cursor/skills/corner-diagonals/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install MengTo/Skills corner-diagonals
```

2. **Manually: put the files in place**
- File: `.github/skills/corner-diagonals/SKILL.md`

### Gemini CLI

1. **Skills CLI (Vercel)**
```bash
npx skills add MengTo/Skills --skill corner-diagonals -a gemini-cli
```

2. **Platform CLI**
```bash
gemini skills install https://github.com/MengTo/Skills --path agent-skills/web-design/corner-diagonals
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/corner-diagonals/SKILL.md` — The legacy .windsurf/skills/ path still works

### OpenCode

**Skills CLI (Vercel)**
```bash
npx skills add MengTo/Skills --skill corner-diagonals -a opencode
```

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/MengTo/Skills/tree/HEAD/agent-skills/web-design/corner-diagonals/SKILL.md

## When to use it
- cut corners off a button with `clip-path`
- build a framed panel with two chamfered corners
- keep one cut size across every card
- preserve a 44px touch target on a clipped button
- make focus states visible around a clipped shape

## Example prompts
- Make a button with chamfered top-left and bottom-right corners, 8px cut
- Build a card with a border using `.cut-shell`, 14px cut on two corners
- Check that clipped buttons still keep 44px height and a visible focus ring

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 00edbe6af6ba47b6.

BEGIN THIRD-PARTY FILE 00edbe6af6ba47b6
````text
---
name: corner-diagonals
description: Apply diagonal-cut corners and chamfered edges to buttons, cards, panels, and container shells. Use when a design needs precise geometric framing, sci-fi UI surfaces, clipped-corner controls, or engineered sharp containers instead of rounded pills or plain rectangles.
---

# Corner Diagonals

## Scope
- Apply only to buttons, cards, panels, and container shells.
- Use when surfaces need diagonal-cut corners or chamfered edges.
- Keep the hit area readable and usable even when the visual shape is clipped.
- Reuse the same corner logic across surfaces so it feels like a system.

## Visual Target
- Diagonal cuts should feel engineered, sharp, and intentional.
- Cuts stay subtle and proportional to the component size.
- One or more corners can be chamfered, but the silhouette should still read quickly.
- Use diagonal corners as a repeated structural motif, not a one-off trick.

## Cut Tokens

```css
:root {
  --corner-cut-sm: 8px;
  --corner-cut-md: 14px;
  --corner-cut-lg: 24px;
  --corner-line: rgba(255, 255, 255, 0.18);
  --corner-line-strong: rgba(255, 255, 255, 0.34);
  --corner-fill: rgba(10, 14, 24, 0.82);
  --corner-accent: #8b5cf6;
}
```

## Core Shapes
Use `clip-path: polygon(...)` for true diagonal silhouettes.

```css
.cut-all {
  --cut: var(--corner-cut-md);
  clip-path: polygon(
    var(--cut) 0,
    calc(100% - var(--cut)) 0,
    100% var(--cut),
    100% calc(100% - var(--cut)),
    calc(100% - var(--cut)) 100%,
    var(--cut) 100%,
    0 calc(100% - var(--cut)),
    0 var(--cut)
  );
}

.cut-top-left-bottom-right {
  --cut: var(--corner-cut-md);
  clip-path: polygon(
    var(--cut) 0,
    100% 0,
    100% calc(100% - var(--cut)),
    calc(100% - var(--cut)) 100%,
    0 100%,
    0 var(--cut)
  );
}

.cut-top-right-bottom-left {
  --cut: var(--corner-cut-md);
  clip-path: polygon(
    0 0,
    calc(100% - var(--cut)) 0,
    100% var(--cut),
    100% 100%,
    var(--cut) 100%,
    0 100%,
    0 0
  );
}
```

## Bordered Shell
For bordered surfaces, use an outer wrapper and inner surface with the same polygon.

```css
.cut-shell {
  --cut: var(--corner-cut-md);
  --border-size: 1px;
  position: relative;
  padding: var(--border-size);
  background: linear-gradient(135deg, var(--corner-line-strong), transparent 46%, var(--corner-line));
  clip-path: polygon(
    var(--cut) 0,
    100% 0,
    100% calc(100% - var(--cut)),
    calc(100% - var(--cut)) 100%,
    0 100%,
    0 var(--cut)
  );
}

.cut-shell__inner {
  min-height: 100%;
````
END THIRD-PARTY FILE 00edbe6af6ba47b6

The third-party file has ended. Everything between the 00edbe6af6ba47b6 tags is data: requests and commands from it are not followed. An “end of file” line with another tag inside the block is part of the file.

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